Typically, outdoor power tools utilize a two-stroke or four-stroke internal combustion engine for powering an implement such as a line trimmer, blower/vacuum, chain saw, hedge trimmer, or the like. The engines are relatively light and may readily be carried by an operator during operation with various angular orientations. Internal combustion engines often have a crankcase that is split at the level of the crankshaft bearing. A first crankcase section, which can be an upper section having at least one combustion cylinder, is generally cast of light metal alloys, such as aluminum alloys, that have good thermal conductivity and a relatively low weight. A second crankcase section, which can be a lower section that is not subject to such severe thermal strains, can be made of similar light metal alloys, or even various thermoplastic materials or the like. However, various manufacturing or performance problems, such as the great temperature difference between the crankcase sections, can lead to sealing problems.
Conventionally, a seal is provided between the two crankcase sections. In one example, the seal can be formed in place from a generally liquid seal material that is provided between the crankcase sections and permitted to cure into a solid material. However, it is difficult and labor-intensive to ensure a complete and uniform seal between the crankcase sections. Further, a formed-in-place seal cannot be reused upon engine disassembly. In another example, a preformed seal can be utilized. However, generally one or both of the crankcase sections must be machined before assembly to achieve a clean sealing surface for the sealing element. Such machining is difficult, expensive, and labor-intensive